J Korean Soc Radiol.  2010 Nov;63(5):475-481. 10.3348/jksr.2010.63.5.475.

MR Imaging of a Posterior Root Tear of the Medial Meniscus: Diagnostic Accuracy of Various Tear Configurations and Associated Knee Abnormalities

• Lee HM
• Shim JC
• Kim JG
• Lee JM
• Nam MY
• Lee GJ
• Kim HK
• Suh JH

• KMID: 2097921
• DOI: http://doi.org/10.3348/jksr.2010.63.5.475

Abstract

PURPOSE
To evaluate the diagnostic accuracy of the various tear configurations in a medial meniscal posterior horn root tear and assess whether any correlation exists with other associated knee abnormalities in MR imaging.
MATERIALS AND METHODS
A retrospective review of 146 preoperative knee MR images were performed by one experienced musculoskeletal radiologist. The tear configuration and other abnormalities were evaluated. Sensitivity, specificity, and diagnostic accuracy of each configuration in the medial meniscal posterior horn root tear were calculated.
RESULTS
A total of 48 medial meniscal posterior horn root tears including 38 full-thickness radial, 7 partial-thickness radial, and 3 complex tears were confirmed during arthroscopy. Overall, the sensitivity, specificity, and accuracy for the detection of medial meniscal posterior horn root tear were 92% (44/48), 99% (97/98), and 97%(141/146), respectively. For each tear configuration, sensitivity, specificity, and accuracy were 82% (31/38), 97% (105/108), and 93% (136/146) for full-thickness radial tears, respectively, and 43% (3/7), 94% (131/139), and 91% (134/146) for partial-thickness radial tears, respectively. The incidence of degenerative joint disease was 85% (41/48) for the tear group, revealing a strong association. In patients with a root tear and with degenerative joint disease, the incidence of high grade cartilage defects involving the medial femoral condyle was at 80% (33/41), compared to 56% (23/41) for the presence of medial meniscal extrusion. In contrast, a similar comparison of incidence for patients with no root tears but with degenerative joint disease was at 68% (17/25) and 26%(8/31), respectively.
CONCLUSION
MR imaging is very sensitive for the detection of medial meniscal root tears, but has reduced the accuracy with regard to each tear configuration. Medial meniscal root tears showed a strong association with degenerative joint disease. High grade cartilage defects of the medial femoral condyle and medial meniscal extrusions also reveal a strong association with medial meniscal root tears.

MeSH Terms

Animals
Arthroscopy
Cartilage
Horns
Humans
Incidence
Joint Diseases
Knee
Magnetic Resonance Imaging
Retrospective Studies
Sensitivity and Specificity

Figure

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  Fig. 1 A 62-year-old woman with a left medial meniscal root tear. Sagittal (arrows, A, B), coronal (arrow, C), and axial (arrow, D) modified turbo spin echo images reveal a full-thickness radial tear, but arthroscopy demonstrated a partial-thickness radial tear.

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  Fig. 2 A 75-year-old man with a right medial meniscal root tear. Sagittal (arrows, A, B), coronal (arrow, C), and axial (arrow, D) modified turbo spin echo images reveal a partial-thickness radial tear, but arthroscopy demonstrated a complex radial tear.

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  Fig. 3 A 66-year-old woman with left medial meniscal root tear. A, B. Coronal modified turbo spin echo images show degenerative joint disease, grade 3 to 4 cartilage lesions of the medial femoral condyle (long arrow), and a medial meniscal extrusion (arrow) with root radial tear (short arrow).

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